The Battle of Artemisium or Artemision was a series of naval engagements over three days during the second Persian invasion of Greece. The battle took place simultaneously with the land battle at Thermopylae, in August or September 480 BC, off the coast of Euboea and was fought between an alliance of Greek city-states, including Sparta, Athens, Corinth and others, and the Persian Empire of Xerxes I.
The Persian invasion was a delayed response to the defeat of the first Persian invasion of Greece, which had been ended by the Athenian victory at the Battle of Marathon. King Xerxes had amassed a huge army and navy, and set out to conquer all of Greece. The Athenian general Themistocles proposed that the Allied Greeks block the advance of the Persian army at the pass of Thermopylae and simultaneously block the Persian navy at the Straits of Artemisium. An Allied naval force of 271 triremes was thus dispatched to await the arrival of the Persians.
Approaching Artemisium towards the end of summer, the Persian navy was caught in a gale off the coast of Magnesia and lost around a third of their 1200 ships. After arriving at Artemisium, the Persians sent a detachment of 200 ships around the coast of Euboea in an attempt to trap the Greeks, but these were caught in another storm and shipwrecked. The main action of the battle took place after two days of smaller engagements. The two sides fought all day, with roughly equal losses; however, the smaller Allied fleet could not afford the losses.
After the engagement, the Allies received news of the defeat of the Allied army at Thermopylae. Since their strategy required both Thermopylae and Artemisium to be held, and given their losses, the Allies decided to withdraw to Salamis. The Persians overran and gained control over Phocis, then Boeotia, and finally entered Attica where they captured the now-evacuated Athens. However, seeking a decisive victory over the Allied fleet, the Persians were later defeated at the Battle of Salamis in late 480 BC. Fearing being trapped in Europe, Xerxes withdrew with much of his army to Asia, leaving Mardonius to complete the conquest of Greece. The following year, however, saw an Allied army decisively defeat the Persians at the Battle of Plataea, thereby ending the Persian invasion.
Background
The Persian emperor Xerxes I decided that the Hellespont had to be bridged for his army to cross to Europe, and that a canal should be dug across the isthmus of Mount Athos. By early 480 BC, the preparations were complete, and the army Xerxes had mustered at Sardis marched towards Europe, crossing the Hellespont on two pontoon bridges.thumb|upright=1.5|Site of the Battle of Artemisium (center). The location of the [[Battle of Thermopylae appears in the lower left corner.]]The Athenians had also been preparing for war with the Persians since the mid-480s BC, and in 482 BC the decision was taken, under the guidance of the Athenian politician Themistocles, to build a massive fleet of triremes that would be necessary for the Greeks to fight the Persians. However, the Athenians did not have the manpower to fight on land and sea; and therefore combating the Persians would require an alliance of Greek city states. In 481 BC, Xerxes sent ambassadors around Greece asking for earth and water, but making the very deliberate omission of Athens and Sparta. Support thus began to coalesce around these two leading states. A congress of city states met at Corinth in late autumn of 481 BC, and a confederate alliance of Greek city-states was formed. It had the power to send envoys asking for assistance and to dispatch troops from the member states to defensive points after joint consultation. This was remarkable for the disjointed Greek world, especially since many of the city-states in attendance were still technically at war with each other.
thumb|300px|A map showing the Greek world at the time of the battle.|alt=A map centered on modern day Greece, Bulgaria and Western Turkey showing the territories of the Achaemenid Empire and the Greek city states.
The 'congress' met again in the spring of 480 BC. A Thessalian delegation suggested that the allies could muster in the narrow Vale of Tempe, on the borders of Thessaly, and thereby block Xerxes's advance. A force of 10,000 hoplites was dispatched to the Vale of Tempe, through which they believed the Persian army would have to pass. However, once there, they were warned by Alexander I of Macedon that the vale could be bypassed through the Sarantoporo Pass, and that the army of Xerxes was overwhelming, the Greeks retreated. Shortly afterwards, they received the news that Xerxes had crossed the Hellespont. However, the Peloponnesian cities made contingency plans to defend the Isthmus of Corinth should all else fail, whilst the women and children of Athens were evacuated en masse to the Peloponnesian city of Troezen.
Prelude
thumb|Beach at [[Cape Artemisium. Magnesia in the distance.]]
The Allied fleet sailed north to Cape Artemisium once it became known that the Persian army was advancing along the coast past Mount Olympus, probably around late July or the beginning of August. The Allies took up station at Artemisium, most likely beaching their ships at the headland, from which they could quickly launch them as needed. The Allies sent three ships to Skiathos as scouts to provide warning of the approach of the Persian fleet but two weeks passed without sight. Finally, ten Sidonian triremes arrived off Skiathos, sent on a scouting mission by the Persian fleet anchored at Therma in Macedonia. Three of these ships crashed into a reef called the Ant/Myrmex, located midway between Skiathos and Magnesia. The main Allied fleet was informed of their arrival by a fire-beacon lit on the island. However, the Allied patrol ships themselves were caught unaware and two were captured, whilst one ran aground. The next day, the Persian fleet finally drew near to Artemisium, heading for the Gap of Skiathos located between the coast of Magnesia and Skiathos, when a summer gale (a 'Hellesponter' – probably a north-easterly storm) broke, driving the Persian fleet onto the mountainous coast. The storm lasted two days, wrecking approximately one third of the Persian ships. Meanwhile, at Thermopylae, the Persians had continued to wait for the Greeks to disperse, also choosing not to attack during the storm. Although clearly storm damaged, the Persian fleet still probably outnumbered the Allies by nearly 3:1. Since the joint operation at Thermopylae and Artemisium was his strategy in the first place, it is likely this is exactly what Themistocles wanted, and this bribe allowed him in turn to bribe the Spartan and Corinthian admirals, Eurybiades and Adeimantus to remain at Artemisium. The Persians did not want to attack the Allies yet, because they thought the Allies would simply flee, and so they sought to trap them. The Allies resolved to go and meet this detachment, to prevent being trapped, though they planned to leave by nightfall to prevent the Persians becoming aware of their plans.
The Allies most likely realised that this situation presented them with an opportunity to destroy an isolated part of the Persian fleet. Herodotus is not clear on where the Allies planned to meet this detachment, only that they resolved to do so. One possibility is that they planned to sail down the Straits of Euboea, and hope that the other Allied ships, patrolling the coast of Attica, followed the Persians as they entered the Straits of Euboea from the south; then the Persians might themselves be caught in a trap.||300||Egypt||150
|-
|Cilicia||100||Ionia||100||Pontus||50
|-
|Pamphylia||30||Cyclades||17
|-
|||||||||Total||1207
|}
Some modern scholars have accepted these numbers, especially since the ancient sources are unusually consistent on this point. Other authors reject this number, with 1,207 being seen as more of a reference to the combined Greek fleet in the Iliad, and generally claim that the Persians could have launched no more than around 600 warships into the Aegean.
Greek fleet
Herodotus claims there were 280 ships in the Greek fleet at the Battle of Artemisium, made up of the following contingents (numbers in parentheses refer to Penteconters, other ships are all Triremes):
{| class=wikitable
!|City!!Number<br>of ships|Ships!!City!!Number<br>of ships|Ships!!City!!Ships
|-
|Athens||127||Corinth||40||Aegina||18
|-
|Chalcis||20||Megara||20||Sicyon||12
|-
|Sparta||10||Epidaurus||8||Eretria||7
|-
|Troezen||5||Styra||2||Ceos||2 (2)
|-
| Opuntian Locris
|(7)||||||Total||271 (9)
|-
|colspan=6|Source:
|}
The Athenians had been building up a large fleet since 483 BC, ostensibly for their ongoing conflict with Aegina. However, it is probable that this build up, initiated by Themistocles, was also made with a future conflict with the Persians in mind. The Athenians initially requested command of the Allied fleet, but let Eurybiades of Sparta command it to preserve unity.
Strategic and tactical considerations
Strategically, the Allied mission was simple. The fleet needed to protect the flank of the army at Thermopylae, whilst not being cut off themselves. For the Persians, the strategic situation was equally simple, although with more options. They needed to force their way through either one of Thermopylae or Artemisium (since holding both was necessary for the Allied effort), or to outflank either position. Outflanking the Straits of Artemisium was theoretically much easier than outflanking Thermopylae, by sailing around the east coast of Euboea. The Greek position at Artemisium may have been chosen in order to watch for such attempts. If narrowness of the channel had been the only determinant, the Allies could have found a better position near the city of Histiaea.
The Persians were at a significant tactical advantage, outnumbering the Allies and having "better sailing" ships. The "better sailing" that Herodotus mentions was probably due to the superior seamanship of the crews; most of the Athenian ships (and therefore the majority of the fleet) were newly built, and had inexperienced crews. The most common naval tactics in the Mediterranean area at the time were ramming (triremes were equipped with a ram at the bows), or boarding by ship-borne marines (which essentially turned a sea battle into a land one). The Persians and Asiatic Greeks had by this time begun to use a manoeuver known as diekplous. It is not entirely clear what this was, but it probably involved sailing into gaps between enemy ships and then ramming them in the side. This maneuver would have required skilled sailing, and therefore the Persians would have been more likely to employ it. The Allies, however, developed tactics specifically to counter this.
Herodotus suggests that the Allied ships were heavier and, by implication, less maneuverable. Their weight would further reduce the likelihood of the Allied ships employing the diekplous. The source of this heaviness is uncertain; possibly the Allied ships were bulkier in construction. Another suggestion is that the heaviness was caused by the weight of fully armoured hoplite marines. The Allies may have had extra marines on board if their ships were less maneuverable, since boarding would then be the main tactic available to them (at the cost of making the ships even heavier). Indeed, Herodotus refers to the Greeks capturing ships, rather than sinking them. However, the Allies had come up with a tactic for this situation, where they turned their "bows on to the barbarians, [and] they drew their sterns together in the middle". This is usually taken to mean that they formed into a circle, with their rams pointing outwards; Thucydides reports that in the Peloponnesian War, Peloponnesian fleets twice adopted a circular formation, with their sterns together. However, Herodotus does not actually use the word circle, and Lazenby points out the difficulty of forming a circle of 250 ships (the Peloponnesian fleets had 30–40 ships). It is thus possible the Allies formed into more of a crescent formation, with the wings drawn back to prevent the Persian ships sailing around the Allied line. Whatever the case, it seems likely that this maneuver was intended to negate the superior Persian seamanship, and perhaps specifically the use of diekplous.
thumb|Disaster hits the Persian fleet off [[Euboea's eastern shore.]]
Having assumed this formation upon the giving of a prearranged signal, the Allied ships moved suddenly outwards from this position at a second signal, rowing into the Persian ships and catching them off guard. This part of the Persian fleet was thus also shipwrecked, losing most of the ships.
Second day
thumb|[[Euboea's eastern shore, the "Hollows", where a large part of the Achaemenid fleet was shipwrecked.]]
The following day (which was also the second day of the battle of Thermopylae) the Persian fleet, now recovering from the two storms, declined to attack the Allies, and instead attempted to make their fleet seaworthy again. Seeing the Persian fleet assemble, the Allies attempted to block the Straits of Artemisium as best they could, and waited for the Persians to attack. The battle raged all day long, with the Allies hard put to defend their line.
thumb|The heavily equipped Egyptians fought successfully against the Greek hoplites.
According to Herodotus, the Athenians were the best fighters on the Allied side. On the Achaemenid side, the best results had been achieved by the Egyptians, who wore a heavy individual equipment comparable to Greek hoplites, and were able to vanquish five Greek ships:
Returning to Artemisium, the Allies saw that they would probably not be able to hold the line for another day, such were their losses. They thus debated whether they should withdraw from Artemisium, whilst they awaited news from Thermopylae. Abronichus arrived on the liaison ship from Thermopylae and told the Allies of the destruction of the Allied rearguard at Thermopylae. Since holding the Straits of Artemisium now no longer held any strategic purpose, and given their losses, the Allies decided to evacuate immediately.
Aftermath
The Persians were alerted to the withdrawal of the Greeks by a boat from Histiaea, but did not at first believe it. They sent some ships to see if this was the case, and finding that it was, the whole fleet set sail for Artemisium in the morning. The Persians then sailed on to Histiaea and sacked the surrounding region.
The Allied fleet sailed to Salamis, off the coast of Attica, to assist with the evacuation of the remaining Athenians. En route, Themistocles left inscriptions addressed to the Ionian Greek crews of the Persian fleet on all springs of water that they might stop at, asking them to defect to the Allied cause: